iOS is the system that powers mobile devices created by Apple. It allows users to operate and customize their devices, and use applications downloadable from the App Store.
iOS applications are built with Apple’s Integrated Development Environment called Xcode, which is a graphical interface for writing apps, and includes everything required to write code for the newest version of iOS.
Apple is making efforts to standardise the native programming language, Swift, for iOS app development, but developers can still use other languages for iOS apps, like Objective-C.
In comparison to Android, writing applications for the iOS operating system can be much more difficult, because it requires meeting Apple’s strict guidelines for applications that can be published in the App Store.
It’s important to review these guidelines in early stages of the project, before development even starts, because failure to do so may result in building an application that one would’ve never been able to publish on the App Store.
What skills should iOS app developers have?
iOS developers should be able to create apps from the ground up, and maintain them over time. They should have no problem using version control systems like Git or SVN, depending on what the project team uses.
Another important aspect is deep understanding of software architecture patterns – like MVC (Model, View, Controller) and MVVM (Model, View, ViewModel).
Developers should know when to apply different patterns, and have the ability to adapt to the architecture of an application that’s already in development. These skills contribute to crafting structured, well-organised code.
Great iOS developers should probably know both of the most popular languages for developing iOS apps – Objective-C and Swift, and have experience writing apps in at least one of them.
Swift is the native language for developing apps for the Apple ecosystem, and Objective-C can be used to develop iOS apps with the Xamarin platform.
One skill that’s growing in importance is Functional Reactive Programming (FRP), which allows developers to easily compose asynchronous operations and event/data streams. This approach creates a lot of new possibilities for developers. Good substitutes for Swift FRP are RxSwift and ReactiveCocoa, and knowing them might also come in handy.
iOS developers should be familiar with dependency managers like CocoaPods, or Carthage, which make it easy to implement libraries into the code base, and keep them up to date.
There are various ways to save data in iOS apps, the simple way being NSUserDefaults. Even though it’s capabilities are limited to managing default user data, it is a valuable tool for iOS app developers to know.
Another important tool is Keychain, a password management system built primarily for securing sensitive data like passwords, certificates, private keys, etc. There’s also CoreData, a framework built by Apple, used for object-oriented communications between applications and databases, and particularly useful for apps that require persistent data.
Moving on, additional important iOS tool are CollectionViews and TableViews. The first one can be used to display lists of items in grid form, with multiple columns and rows, scrollable horizontally and vertically. The second tool is used to display a single-column, vertically scrollable list of items.